It is well known that more than 70% of illnesses affecting the digestive tract are of a functional nature. Today such illnesses are treated predominantly using pharmacological means. Since drugs generally have side effects, particularly when the drugs cure the symptom and not the underlying problem or dysfunction, they must often be administered temporally. Indeed, if the side effects are sufficiently serious, the drug may have to be discontinued before full benefit to the patient is realized; in many cases the underlying illness remains.
The important role played by electrophysiology in controlling gastrointestinal activity has become increasingly apparent in recent years. Thus, the possibility exits of correcting dysfunction by means of electrostimulation applied at specific frequencies, sites, and modalities and with regard to the self-regulating electromotor physiology of the gastrointestinal tube. It has recently been shown, for example, that changes occur in the motility and electromotor conduct of the gastric tract in eating disorders (e.g., obesity, thinness, bulimia, anorexia). Disturbances in electromotor activity in diabetic gastroparesis, in reflux in the upper digestive tract, and in numerous other gastroenterological functional pathologies have also been observed.
Stimulation of the intrinsic nervous system of the stomach is likely to have two major consequences or effects: (1) the correction and direct control of the electromotor activity of the intestines and (2) the stimulation of increased incretion of specific substances (i.e., gastroenteric neuromediators) produced by the intrinsic nervous system itself through the myenteric plexus. Curing of functional illnesses involving the digestive system and more broadly involving disorders in any way connected to the digestive system is, therefore, closely linked to the progress of research in the field of electrophysiology.
An indispensable condition for modifying the electrical activity of the digestive system's intestinal tract and the related neurohormonal incretions is the use of an implant system to generate electrical impulses (electrical stimuli) and electric tubes (electrocatheters) to connect them to the viscera and/or intestines to be stimulated. These treatment methods involve a surgical technique to implant the electrocatheter in the abdomen which is known as micro-invasive surgery or video-laparoscopic surgery. Current electrocatheters to stimulate electrically and/or monitor endo-abdominal viscera normally have metal microbarbs which are angled in such a way as to permit application of the end of the catheter and to prevent it from being dislodged. However, this type of catheter is often very complicated to make and consequently is very costly.
Moreover, current electrocatheters are generally very difficult to handle and use. More particularly, surgeons generally find them very difficult to insert because of the many arduous operations required to be performed during the laparoscopic procedure. In such procedures, the patient is first given a general anesthetic, after which his or her abdomen is inflated with CO.sub.2 or another inert inflammable gas so as to transform the abdominal cavity from a virtual to a real cavity. Rigid tubes with air-tight membranes (i.e., "trocars") are then inserted into the abdominal cavity filled with CO.sub.2 so that a video camera and other surgical instruments can be introduced into the abdomen. The operation then proceeds by viewing the video images transmitted by the camera. Normally four or more trocars are used. Generally the first trocar provides access to the abdomen by the video camera in order to monitor the surgical procedure. A service clamp is normally inserted in the second trocar to move or retain the hepatic edge that normally covers the small gastric curve or other viscus depending on the type of operation to be performed. A third trocar provides access for a maneuvering clamp or laparoscopic forceps. The fourth trocar is used for the introduction of the electrocatheter to be implanted in the patient. The structure of the electrocatheter plays an important part in facilitating the specific operation for whichever of the patient's viscera the surgeon aims to stimulate.
Each of the trocars used, of course, requires a separate incision through the skin. To keep the abdomen inflated, valves are used with the trocars, allowing for an airtight seal. Introduction of a medical device, such as an electrocatheter, into the abdomen generally requires the use of laparoscopic forceps to grasp the device. Such devices, which are generally inherently fragile in nature, could be damaged if grasped too firmly by the forceps. Thus, for example in the case of an electrocatheter having electrode leads, the interior conductor wires could be broken, rendering the device useless.
It is, of course, desirable in laparoscopic surgery to limit the number of trocars used since each trocar requires a separate incision which results in additional visible scars for the patent. More importantly, each additional incision increases the chance of infection and other complications resulting therefrom. Therefore, to eliminate an additional trocar, implantable devices are often inserted completely through the trocar and into the abdomen so that the trocar can be used for insertion of other instruments and/or manipulation devices. Thus, the surgeon will often need to pull the distal end of the inserted device back through a trocar and/or remove the device entirely. In this case, the device needs to "line up" to the trocar passageway to be pulled back through the trocar. Of course, if the device is grasped by the forceps in a manner so the longitudinal dimension of the device is not aligned with the trocar passageway, the device cannot be pulled back through the trocar.